Rock Polish Genesect : Quite threatening
However, I don't know if it has been mentioned or not, but if Genesect does not receive any form of a boost, it will honestly not be that great.
If it carries Giga Drain over ThunderBolt, Tentacruel, from my experience, was able to play with the thing all day.
If it carries T-Bolt, I'm pretty sure Rotom-W Bulky Varients, can WoW and Pain Split and pretty much laugh at RP Genesect too :/
TaBuu : Pokemon Legend